1. Field of the Invention
The present invention relates in general to a container for protectively containing semiconductor integrated circuit wafers. In particular, the present invention relates to a container for securely and protectively containing a number of semiconductor integrated circuit wafers that is easy to access and handle.
2. Description of Related Art
Wafer containers are utilized to hold the IC wafers in the process of IC device fabrication. C. J. Wu et al. disclosed an IC wafer container in U. S. Pat. No. 4,787,508, the subject matter of which is hereby incorporated by reference as if fully set forth herein. The Wu et al container comprises a body member and its corresponding enclosure member.
FIG. 1 (Prior Art) of the accompanying drawings is a perspective view of a conventional IC wafer container including a body member and an enclosure member. As shown in the drawing, it is opened for insertion or removal of IC wafers. This known IC wafer container 1 has a body member 10 for containing the wafers and an enclosure member 20 for covering the body member 20 when required. When enclosure member 20 is fitted over body member 10, the container is a substantially cylindrical shape. Body member 10 and enclosure member 20 are threaded so that they can be secured to one another.
To store the wafers in the container, the covering enclosure member 20 must be removed from the body member 10, revealing an open end 120 for inserting or removing IC wafers, not shown in the drawing. During normal use of container 1, the body member 10 must be placed in the upright position with its closed end 110 below and its open end 120 above. IC wafers having a diameter compatible with the inner diameter of the body member 10 may be stored inside by successively stacking one wafer after another from the bottom up.
A number of longitudinal openings 130, for example, four in this referenced prior art example, are cut in the sidewall of the body member 10 parallel to the longitudinal axis thereof. This allows for the easy handling of the wafers when inserting them or removing them from the container. The edge of a wafer may be held when it is inserted or removed.
A helical screw threading 140 is formed near the closed end 110 of the body member 10 that is capable of threadingly engaging with the corresponding screw threading, not shown, and formed on the internal sidewall of the enclosure member 20 near the open end 220 thereof. The corresponding threading of both the body and enclosure members allows them to be secured to one another.
The enclosure member 20 has the basic structural configuration of a cylindrical cover sealed at the closed end 210 and opened at the open end 220. The open end 220 allows the enclosure member 20 to receive the open end 120 of the body member 10. On the top surface of the enclosure member 20, an annular indentation 230 is formed that in turn forms the circular protuberance 240 that allows for the grip of the fingers of a user when the enclosure member 20 is to be threaded in or out of engagement with the body member 10, or when it is to be lowered toward or raised from the body member 10. A ring-shaped surface 250 is formed on the closed end 210 of the enclosure member 20, which results in a short section of the cylindrical body with reduced diameter.
However, the prior art IC wafer container suffers from several disadvantages. First, the diameter of the circular protuberance 240 and the width of the annular indentation 230 on the top surface of the closed end 210 of the enclosure member 20 are essential for the smooth handling of its installation on and detachment from the body member 10. The width of the annular indentation 230 must be sufficient for the finger tips of a user to enter, while, on the other hand, the diameter of the circular protuberance 240 must be sufficiently large to reduce the rotational force that must be provided by the user in order to create sufficient torque to turn the enclosure member 20 relative to body member 10 when closing or opening the container. In the prior art arrangement, it is impossible to enlarge both the diameter and width of the circular protuberance 240 and the annular indentation 230.
Moreover, the threaded arrangement of this prior art IC wafer container requires that the user make multiple rotations of the enclosure member 20 against the body member 10 to close or open the container. This is rather inconvenient.
Furthermore, unless the entire wafer storage room within the container is filled with wafers, the container should never be tilted, either with or without the covering enclosure member 20 installed in place. Soft padding material must be inserted in the empty space above the stack of stored wafers inside the body member 10, in the case of partial containment of the container. Without this padding, the contained wafers may be damaged when the container is moved.